1. Field of the Invention
The present invention generally relates to visible light communication, and more particularly, to an apparatus for transmitting and receiving data by a wavelength division multiplexing method.
2. Description of the Related Art
Recently, concerns about optical wireless technology that is complementary with RF technology have been increasing due to the exhaustion of RF (Radio Frequency) bands, the possibility of crosstalk among several wireless communication technologies, increasing requirements for communication security, introduction of an ultrahigh speed ubiquitous communication environment of the 4G wireless technology, etc.
In particular, since visible light communication for transferring information using visible light is safe, and has wide-use bands, visible light communication can be freely used without any restrictions. Also, since the light destination or the direction of travelling light can be seen, the reception range of information can be recognized accurately. Visible light communication also has reliable security, and can be driven by low power to reduce power consumption. In addition, visible light communication can be applied to hospitals and airplanes in which the use of radio frequencies is limited, and can provide additional information services using electric signboards. Accordingly, research into visible light wireless communication has been made in many companies and research institutes.
Further, visible light communication enables data transmission by a wavelength division multiplexing method using different visible light wavelength bands. Accordingly, it becomes possible to transmit different data, which correspond to different wavelengths, using Light Emitting Diodes (LEDs) generating a plurality of colored visible lights (e.g., red, green, and blue visible lights).